Air Versus Saline in Tissue Expanders: A Systematic Review of the Literature.

BACKGROUND: There has been a greater focus in recent literature proposing air to be a superior medium to saline in tissue expanders. This study aims to review the literature and assess the quality of data on the efficacy and safety of air as an alternative medium to saline in tissue expanders, in the setting of postmastectomy two-stage reconstruction. METHODS: A systematic review regarding air inflation of tissue expanders was conducted using PubMed, Embase, Cochrane Library, and Web of Science. The methods followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Three reviewers separately performed data extraction and comprehensive synthesis. RESULTS: A total of 427 articles were identified in our search query, of which 11 met the inclusion criteria. Three pertained to inflation with room air, and eight pertained to inflation with CO2 using the AeroForm device. They were comparable to decreased overall complication rates in the room air/CO2 cohort compared to saline, although statistical significance was only observed in one of five two-arm studies. Investigating specific complications in the five two-arm studies, significantly lower rates of skin flap necrosis were only observed in two CO2-based studies. Studies rarely discussed other safety profile concerns, such as the impacts of air travel, radiation planning, and air extravasation beyond descriptions of select patients within the cohort. CONCLUSION: There is insufficient evidence to suggest improved outcomes with room air inflation of tissue expanders. Further work is needed to fully characterize the benefits and safety profiles of air insufflation before being adopted into clinical practice.

Corset Autodermis External Obliqueplasty Reinforcement of Rectus Diastasis and Umbilical Hernia Repairs during Abdominoplasty.

SUMMARY: Abdominoplasty is among the most commonly performed aesthetic operations and is frequently combined with rectus abdominis musculoaponeurotic plication of rectus diastasis and repair of umbilical and ventral hernias. The authors present a spare parts technique to assist in reinforcement of both rectus diastasis plication and hernia repair during abdominoplasty operations using an autodermis onlay reinforcement graft. The graft is harvested from the excess abdominal pannus normally discarded during abdominoplasty and is inset on tension between the bilateral semilunar lines and plicated along a concave "corset" contour. This reduces distracting forces on the hernia and diastasis repairs and further augments abdominal contour. This technique has been performed for 8 years on 82 low-surgical-risk patients, without any noted increase in complications. The corset autodermis external obliqueplasty is a spare parts technique that may reduce recurrence of rectus diastasis and abdominal hernias repaired at the time of abdominoplasty and is an alternative strategy to mesh placement in this risk-averse aesthetic surgery population.

Increasing Fat Graft Retention in Irradiated Tissue after Preconditioning with External Volume Expansion.

BACKGROUND: Fat grafting is an adjuvant that may improve the quality of radiation-damaged tissue. However, fat grafting for volume restoration in irradiated sites may be less effective because of a poorly vascularized fibrotic recipient bed. External volume expansion has emerged as a potential technique to prepare the recipient sites for improved survival of grafted fat. The authors previously demonstrated increased vasculature with external volume expansion stimulation of irradiated tissues. The authors now hypothesize that external volume expansion's improvements in recipient-site vascularity will increase the volume retention and quality of fat grafts in fibrotic irradiated sites. METHODS: Athymic mice were irradiated until development of chronic radiation injury. Then, the irradiated site was stimulated by external volume expansion (external volume expansion group), followed by subcutaneous fat grafting. Grafts in an irradiated site without external volume expansion stimulation (irradiated control group) and grafts in a healthy nonirradiated (nonirradiated control group) site were used as controls. All grafts were monitored for 8 weeks and evaluated both histologically and by micro-computed tomography for analysis of volume retention. RESULTS: Hyperspectral imaging confirmed a 25 percent decrease in vascularity of irradiated tissue (irradiated control group) compared with nonirradiated tissue (nonirradiated control group). Grafts in the irradiated control group retained 11 percent less volume than grafts in the nonirradiated control group. The experimental external volume expansion group achieved a 20 percent (p = 0.01) increase in retained graft volume compared with the irradiated control group. CONCLUSIONS: External volume expansion stimulation can mitigate the effects of irradiation at the recipient site and in turn help preserve fat graft volume retention. Possible mechanisms include increased vascularity, adipogenic conversion, and increased compliance of a fibrotic recipient site.

Hyperspectral Imaging Provides Early Prediction of Random Axial Flap Necrosis in a Preclinical Model.

BACKGROUND: Necrosis remains a significant complication in cutaneous flap procedures. Monitoring, and ideally prediction, of vascular compromise in the early postoperative period may allow surgeons to limit the impact of complications by prompt intervention. Hyperspectral imaging could be a reliable, effective, and noninvasive method for predicting flap survival postoperatively. In this preclinical study, the authors demonstrate that hyperspectral imaging is able to correlate early skin perfusion changes and ultimate flap survival in a preclinical model. METHODS: Thirty-one hairless, immunocompetent, adult male mice were used. Random pattern dorsal skin flaps were elevated and sutured back into place with a silicone barrier. Hyperspectral imaging and digital images were obtained 30 minutes, 24 hours, or 72 hours after flap elevation and before sacrifice on postoperative day 7. RESULTS: Areas of high deoxygenated hemoglobin change (124; 95 percent CI, 118 to 129) seen at 30 minutes after surgery were associated with greater than 50 percent flap necrosis at postoperative day 7. Areas demarcated by high deoxygenated hemoglobin at 30 minutes postoperatively had a statistically significant correlation with areas of macroscopic necrosis on postoperative day 7. Analysis of images obtained at 24 and 72 hours did not show similar changes. CONCLUSIONS: These findings suggest that early changes in deoxygenated hemoglobin seen with hyperspectral imaging may predict the region and extent of flap necrosis. Further clinical studies are needed to determine whether hyperspectral imaging is applicable to the clinical setting.

External Volume Expansion in Irradiated Tissue: Effects on the Recipient Site.

BACKGROUND: External volume expansion prepares recipient sites to improve outcomes of fat grafting. For patients receiving radiotherapy after mastectomy, results with external volume expansion vary, and the relationship between radiotherapy and expansion remains unexplored. Thus, the authors developed a new translational model to investigate the effects in chronic skin fibrosis after radiation exposure. METHODS: Twenty-four SKH1-E mice received 50 Gy of ß-radiation to each flank and were monitored until fibrosis developed (8 weeks). External volume expansion was then applied at -25 mmHg to one side for 6 hours for 5 days. The opposite side served as the control. Perfusion changes were assessed with hyperspectral imaging. Mice were euthanized at 5 (n = 12) and 15 days (n = 12) after the last expansion application. Tissue samples were analyzed with immunohistochemistry for CD31 and Ki67, Masson trichrome for skin thickness, and picrosirius red to analyze collagen composition. RESULTS: All animals developed skin fibrosis 8 weeks after radiotherapy and became hypoperfused based on hyperspectral imaging. Expansion induced edema on treated sides after stimulation. Perfusion was decreased by 13 percent on the expansion side (p < 0.001) compared with the control side for 5 days after stimulation. Perfusion returned to control-side levels by day 15. Dermal vasculature increased 38 percent by day 15 (p < 0.01) in expansion versus control. No difference was found in collagen composition. CONCLUSIONS: External volume expansion temporarily reduces perfusion, likely because of transient ischemia or edema. Together with mechanotransduction, these effects encourage a proangiogenic and proliferative environment in fibrotic tissue after radiotherapy in the authors' mouse model. Further studies are needed to assess these changes in fat graft retention.